Genetic and Phenotypic Landscape of PRPH2-Associated Retinal Dystrophy in Japan.

Akio Oishi,Shinji Ueno,Makoto Nakamura,Akitaka Tsujikawa,Takeshi Iwata,Sentaro Kusuhara,Kaoru Fujinami,Nobuhisa Naoi,Hiroyuki Kondo,Takaaki Hayashi,Kazuki Kuniyoshi,Kei Shinoda,Kazushige Tsunoda,Atsushi Mizota,Yasuhiro Ikeda,Go Mawatari

doi:10.3390/genes12111817

Abstract

Peripherin-2 (PRPH2) is one of the causative genes of inherited retinal dystrophy. While the gene is relatively common in Caucasians, reports from Asian ethnicities are limited. In the present study, we report 40 Japanese patients from 30 families with PRPH2-associated retinal dystrophy. We identified 17 distinct pathogenic or likely pathogenic variants using next-generation sequencing. Variants p.R142W and p.V200E were relatively common in the cohort. The age of onset was generally in the 40’s; however, some patients had earlier onset (age: 5 years). Visual acuity of the patients ranged from hand motion to 1.5 (Snellen equivalent 20/13). The patients showed variable phenotypes such as retinitis pigmentosa, cone-rod dystrophy, and macular dystrophy. Additionally, intrafamilial phenotypic variability was observed. Choroidal neovascularization was observed in three eyes of two patients with retinitis pigmentosa. The results demonstrate the genotypic and phenotypic variations of the disease in the Asian cohort.

Highlights

Inherited retinal dystrophy (IRD) refers to a group of diseases characterized by progressive retinal cell death, photoreceptor cell death, caused by genetic mutations.More than 300 causative genes have been reported to date, with a considerable overlap [1].Recently, gene therapy has become available to patients with pathogenic variants of a specific gene, and other trials are ongoing [2]
In addition to the phenotype subgroups, we investigated the presence of clinical factors such as macular atrophy, peripheral atrophy, Best disease-like deposits, and multiple flecks on retinal imaging because some patients showed overlapping phenotypes and clinical diagnosis may obscure the characteristics (Figure 1)
While this study focused on PRPH2, the screening was conducted as a part of comprehensive genetic screening of patients with IRD

Summary

Introduction

Inherited retinal dystrophy (IRD) refers to a group of diseases characterized by progressive retinal cell death, photoreceptor cell death, caused by genetic mutations.More than 300 causative genes have been reported to date, with a considerable overlap [1].Recently, gene therapy has become available to patients with pathogenic variants of a specific gene, and other trials are ongoing [2]. Inherited retinal dystrophy (IRD) refers to a group of diseases characterized by progressive retinal cell death, photoreceptor cell death, caused by genetic mutations. More than 300 causative genes have been reported to date, with a considerable overlap [1]. Omim.org/ accessed on 17 November 2021) is one of the causative genes of IRD. The gene is generally associated with an autosomal-dominant inheritance pattern, but autosomal recessive [5] and digenic patterns in conjunction with retinal outer segment membrane protein 1 (ROM1) has been reported [6,7]. Pathogenic variants of PRPH2 may cause diverse phenotypes such as retinitis pigmentosa (RP), retinitis punctata albescens, cone/cone-rod dystrophy (CRD), and macular dystrophies (MD) [3,8–10]. The presence of ROM1 variants may modify these phenotypic appearances [14] or increase the severity of the disease [15]

Methods

Results

Conclusion